ABSTRACT

The most important centre of diversity and endemism of columnar cacti in Mexico is the Tehuacán-Cuicatlán Valley (Puebla-Oaxaca states). The aims of this paper are (1) to provide a detailed description of the recent pollen morphology of 19 registered species that are found in this valley and (2) to develop a synoptic table to differentiate groups of species. This synoptic table is based on morphological features of pollen grain and the density of structural and sculptural elements observed using light and scanning electron microscopy. All analysed pollen grains were stenopalynous: isopolar monads, large, tricolpate with perforate tectate exine (sexine-nexine ratio 1:1), columellate structure with pattern of columellae distribution and spinulose sculpture. The spinules were always wider than they were tall. Although the 19 species of columnar cacti analysed in this study show highly similar types of pollen grains, we were able to characterise each of them with combined microscopy techniques.

摘要

墨西哥最重要的柱状仙人掌多样性和特有中心是特瓦坎-奎卡特兰山谷（普埃布拉-瓦哈卡州）。本文的目的是 (1) 详细描述该山谷中发现的 19 种已登记物种的最新花粉形态；(2) 开发一个概要表来区分物种组。该概要表基于花粉粒的形态特征以及使用光学和扫描电子显微镜观察到的结构和雕塑元素的密度。所有分析的花粉粒都是狭花粉粒：等极单子、大、三沟，具有穿孔的硬质外壁（内壁比1:1）、柱状结构，具有小柱分布模式和刺状雕刻。小刺的宽度总是大于高度。